当0-9处于条件时,为什么某些符号会传递正则表达式?

我需要用PHP编写一个正则表达式,条件是 A-Z, a-z, 0-9 , : , - , _ ,但字符串末尾不能为 :

这就是我试过的

<?php

$strings = [
    'aaa:bbb-cool',
    'aaa:bbb-cool-',
    'aaa-22-bbb_cool3',
    'aaa:bbb-cool:',
    'aaa_bbb-cool:',
    'aaa_bbb-cool',
    'bbbb:>dd',
    'hihi%',
    '大家好',
    '0000000000',
    '11111:2222:3333',
    '11111:2222:3333:',
    'DDD@@@1',
    '大家好',
];

$pattern = '/[0-9a-zA-Z]+$/i';

foreach ($strings as $key => $string) {
    var_dump('number '.$key .' '. $string.' is '.preg_match($pattern, $string));
}

结果是

string(26) "number 0 aaa:bbb-cool is 1"
string(27) "number 1 aaa:bbb-cool- is 0"
string(30) "number 2 aaa-22-bbb_cool3 is 1"
string(27) "number 3 aaa:bbb-cool: is 0"
string(27) "number 4 aaa_bbb-cool: is 0"
string(26) "number 5 aaa_bbb-cool is 1"
string(22) "number 6 bbbb:>dd is 1"
string(19) "number 7 hihi% is 0"
string(23) "number 8 大家好 is 0"
string(24) "number 9 0000000000 is 1"
string(30) "number 10 11111:2222:3333 is 1"
string(31) "number 11 11111:2222:3333: is 0"
string(22) "number 12 DDD@@@1 is 1"
string(24) "number 13 大家好 is 0"

1. 我知道我并不是真的阻止”:“最终,原因1应该是真的,如何纠正它
2. 为什么数字6和数字12是真的?